diff --git a/go-demo-4/cloud/cloud.go b/go-demo-4/cloud/cloud.go
new file mode 100644
index 0000000..54ffe94
--- /dev/null
+++ b/go-demo-4/cloud/cloud.go
@@ -0,0 +1,19 @@
+package cloud
+
+type CloudDb struct {
+	url string
+}
+
+func NewCloudDb(url string) *CloudDb {
+	return &CloudDb{
+		url: url,
+	}
+}
+
+func (db *CloudDb) Read() ([]byte, error) {
+	return []byte{}, nil
+}
+
+func (db *CloudDb) Write(content []byte) {
+
+}